how can scientist know what's inside earth's core when no one has been inside?

Question

This bugs me as how can they say we have molten rock in the middle, different layers and etc. when no one has actually been inside..

Answer 1

Although some of the people trying to answer are clueless, this is actually a very good question which any scientist would be happy to hear from a student. It's exactly questions like this that make science work, and scientists ask this kind of question all the time.

Scientists don't just make pronouncements without any evidence. What they do is collect evidence and then try to imagine a model that, if its exists, would result in that evidence. So, if you look at the magnetic fields of the Earth and how they change, and the density and gravity of the Earth, and the kinds of materials that are ejected in different volcanos, etc and try to imagine what structure the Earth would have that would produce all those results, then you can make a model. AS time goes on, people find more and more facts, and the model gets changes so that it accounts for both the old facts and the new facts. After a while you have a model that is very reliable and allows you to make solid predictions about how the Earth operates.

If you asked any geologist about whether the descriptions of the center of the Earth are absolutely true, they would tell, you , Not absolutely, but they are the best educated guess we can make, based on the evidence we have.

ps there are no scientists who think that the center of the earth is full of big caves! That's BS.

Answer 2

There are basically three lines of evidence that we use to figure out what is at the center of the Earth. The first line of evidence is Earth's average density. We can determine this by measuring the amount of gravity that Earth generates (this tells us its mass) and compare that to Earth's volume. When we doe this, we find that Earth's average density is about 5.5 g/cm^3. However, the average density of the silicate rocks that comprise the mantle and crust are only about 3.3 g/cm^3. This tells us that there must be something down there that is a whole lot denser than rock.

The second line of evidence comes from seismic waves. In the laboratory, we can determine how fast seismic waves travel through various types of rocks under the various temperature and pressure conditions that exist inside of the Earth. With this information, we can then use seismic waves to peer into the Earth and determine what is down there. This works in pretty much the same way that a CAT scanner uses x-rays to create a 3D image of the inside of a person's body without cutting them open. Using these waves, we can tell that there is something down there that has very different properties than would have rock under the same conditions.

Finally, we have meteorites. Meteorites are the debris that is left over from the formation of the planets that lands on the surface of the Earth. It is assumed that, when taken all together, they represent a pretty good approximation of the materials that were available when Earth was forming. When we look at the overall composition of the meteorites, we find a much higher concentration of metallic iron and nickel than we see in the rocks that make up the crust and mantle. So, where did this excess iron go?

When we take these three lines of evidence and put them together, we get an iron-nickel core at Earth's center. Iron and nickel in the proportions that we see in meteorites would have sunk to the center of the Earth to create the core that is evident in the seismic data. Furthermore, it would behave the way the seismic data indicates the core behaves. Additionally, iron and nickel in the proportions that we find in the meteorites and in the quantity that is represented by Earth's core would add the necessary mass to bring Earth's average density up to 5.5 g/cm^3.

So, these are the lines of evidence that tell us of what Earth's core is made. It is all circumstantial, but it still makes for a good case. I know of no other theory that can come close to matching this one.

BTW, for those that say that we have samples of the core coming out of volcanoes, sorry, but no. The material of the core is too dense to be able to make it's way to the surface. I actually sank down there early in Earth's formation. It is going to stay down there until the Sun turns into a Red giant and swallows Earth.

Answer 3

How can science say anything about anything? Do you doubt the existance of atoms, or of their constituent parts: protons nuetrons and electrons? Nobody has seen any of these particles, yet much of the technological developments of the 20th century were from our understanding of these theories. Through the development and testing of theories. In the case of the Earth's interior, including the core, the answer is Geophysics, using the tools of Seismology. This is supplimented by studying various types of meteorites. If you don't believe either of these methods then you need to close your mind to Science, because no amount of evidence will satisfy you.

Answer 4

There are some scientists which believe there isn't molten rock at the center of the earth, but that it is indeed a series of caves within the earth. No matter what anyone tells you, we do NOT know for sure! And good for you for asking important questions like this! :)

Answer 5

Well scientists are about theories. and many of them are based on laws. They studied for years and years and they noticed the the different layers of the earth and they probably noticed that the heat increases as they reach closer to the core. Also their are volcanoes and the study of those lead to the earth's core as well.

Answer 6

come on now..the movie Journey To The Center Of The Earth..
didn't you see it...
a lot of scientist did...

plus when they go into dead volcano's..they look at the structures and when the active volcano's erupt, the take all that into account and use their science on it all..

good luck
smile

Answer 7

Our core comes to the surface in volcano's. We get our information from those

Answer 8

Take a look at this article, it explains it a bit better than I can...

http://en.wikipedia.org/wiki/Earth%27s_core

Answer 9

Good question. You will probably get a hundred NON provable answers.

Answer 10

"supposedly" we know because of volcanoes and tectonic plates